4 ways to effectively monitor total chlorine in liquid hydrocarbons

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Corrosion at petroleum refineries is a critical problem all over the world. In the United States alone, NACE International, a professional association dedicated to reducing the economic impact of corrosion, has shown that $3.7 billion in direct costs are realized annually from maintenance, vessel expenditures,
and fouling as a result of corrosion.1 This huge figure does not take into account the estimated loss of as much as $12 billion in profits due to decreased capacity, unit outages, and premature turnarounds that result from corrosion.2

CHALLENGE
Chlorine in crude oil, if not removed, can hydrolyze during processing to form hydrochloric acid. The crude oil desalter is the first line of defense in the prevention of corrosion, but in order to provide a proper defense, an effective chloride monitoring solution must be implemented. Many refiners rely on semiperiodic testing of inorganic chlorides to get the job done. However, what if a desalter upset occurs in between testing periods? Worse yet, what if an organic chlorine slug is present in the incoming crude? The desalter will remove only the extractable inorganic chlorides, not organic chlorides, and any
chlorides that pass through the desalter have the potential of causing fouling and corrosion issues.
Even refiners who don’t rely on semi-periodic testing typically only monitor inorganic chlorine. While this is very important for desalter efficiency, it does not capture all threats.

INTRODUCTION
Since its launch in 2007, Clora® Benchtop Analyzer has been widely adopted by refineries and test labs for monitoring chlorine in petroleum. With over 200 systems in the field, XOS customers know they can trust Clora for testing products from crude oil to naphtha cuts and VGO. In 2011, XOS launched Clora Online; an online analyzer that delivers continuous, real-time chlorine analysis in liquid hydrocarbon and aqueous process streams. In this paper, we will discuss the most popular Clora benchtop and online procedures utilized by petroleum laboratories around the world to measure total chlorine for corrosion mitigation:
1. Organic Chlorides by ASTM D4929
2. Total Chlorine by Modified ASTM D7536 with Accu-flow
3. Online Chlorine Analysis in Crude Oil and Petroleum Process Streams
4. Organic and Inorganic Chlorides Using Water Extraction